CROM provides 2 diagnostic tests for Complex Regional Pain Syndrome (CRPS); Quantitative Sudomotor Axon Reflex Test (QSART) and Infrared Stress Thermography. CROM treats patients with CRPS in the Denver area.
What is Complex Regional Pain Syndrome ?
Complex regional pain syndrome (CRPS) is an uncommon neurological condition characterized by pain, inflammation and changes in the skin sensation and appearance. Patients may have a burning sensation in the arms, legs, hands or feet. Treatments are available for this condition, and the disease can be mild or severe, and wide variation is seen in different patients in the course of this condition over time.
The condition has been known by many different names in the past including, most recently, reflex sympathetic dystrophy (RSD). There is no agreement on the cause of CRPS.
Generally, injury, immobilization, or previous surgery may be a catalyst for the onset of symptoms, but it is not understood why or how complex regional pain syndrome uncommonly occurs in some patients, even though most patients heal without problems. In very rare cases, no evidence of prior injury can be identified prior to the occurrence of CRPS.In general, treatment is more successful when initiated early in the course of the condition, so early and accurate diagnosis is very important.
Diagnostic Tests for Complex Regional Pain Syndrome
In patients with Complex Regional Pain Syndrome, abnormalities of the sympathetic nervous system are present. Generally, there is more variability than normal in the function of this part of the nervous system. Since the blood vessels, which control skin temperature, are controlled by the sympathetic nervous system, there are often abnormalities in skin temperature present in patients with this problem which can be used to diagnose the presence or absence of Complex Regional Pain Syndrome.
Normally, the body maintains quite similar temperatures from side to side. Even if slight temperature differences are present, these differences usually are not persistent when the overall body is exposed to cold stress. Different specific patterns of side to side temperature differences may reflect medical problems in the underlying muscle, joints, nerves, or blood vessels. There are some patterns of temperature differences which can indicate the presence of complex regional pain syndrome.
Thermography is a visual mapping of skin temperature recorded by a specialized camera sensitive to the infrared spectrum. To diagnosis CRPS, three sets of 10 to 12 images each are recorded with the patient exposed to a cold stress (67 degrees Fahrenheit) environment. When a specially trained physician evaluates thermographic images obtained in accordance with specific standard protocols, a determination can be made in most cases whether CRPS is present or not.
The Colorado Division of Workers Compensation Medical Treatment Guidelines require that two objective tests be positive to diagnose confirmed CRPS. Both Stress Thermography and the Autonomic Testing Battery (see below) are listed as objective tests which may be used to diagnose CRPS. Colorado Rehabilitation and Occupational Medicine is the only medical practice in Colorado performing both diagnostic evaluations. CROM physician Dr. Tashof Bernton has received advanced training in obtaining and interpreting diagnostic thermographic testing and are both physicians are certified by the American Academy of Thermology.
Autonomic Testing Battery/ Quantitative Sudomotor Axon Reflex Test
Colorado Rehabilitation and Occupational Medicine also offers the Autonomic Testing Battery as a diagnostic test for Complex Regional Pain Syndrome.
Temperature and sweating are both controlled by the sympathetic nervous system and normally both functions are symmetric from side to side in the arms and in the legs. In Complex Regional Pain Syndrome, the sympathetic nervous system has abnormalities resulting in greater than normal variation in these functions. By measuring baseline temperature, baseline sweating, and sweating after stimulation with acetylcholine (a naturally occurring neurotransmitter which stimulates the sweat glands) the amount of variation in these functions from side to side can be evaluated in a quantitative manner. This last test (measurement of sweating after stimulation with acetylcholine), is also known as the Quantitative Sudomotor Axon Reflex Test or QSART. Sometimes, the entire Autonomic Testing Battery is referred to informally as a “QSART” test, although technically the QSART is only one component of the Autonomic Testing Battery.
The results of the entire Autonomic Testing Battery are integrated with a clinical examination of the patient to determine whether or not the patient meets diagnostic criteria for Complex Regional Pain Syndrome.
Colorado Rehabilitation and Occupational Medicine Physician Dr. Tashof Bernton has attended advanced training at the Mayo Clinic in the administration and evaluation of the Autonomic Testing Battery and have performed Autonomic Testing for over 10 years.
The Autonomic Testing Battery begins with thermographic imaging to measure resting skin temperatures. Next, small plastic cups will be placed on the patient’s skin to measure resting sweat output. The procedure is painless.
After these baselines have been established, physical therapy iontophoresis pads are placed on the skin to deliver a naturally occurring nerve chemical, acetylcholine, to stimulate the sweat glands. Sweat output is measured after this stimulation and side to side comparisons are performed. You may experience slight tingling in this test, but it is not painful and needles are not used. The entire process will takes 2-3 hours.
Testing Requirements-Both Thermography and ATB
All medications must be reviewed by CROM physicians prior to your testing. There are some medications which can interfere with the testing protocol, and these medications may need to be stopped for a period of time prior to the test. If you are on any medications which may interfere with the test, CROM physicians can speak with you or your physician if there are any questions regarding the safety of temporarily stopping specific medications, or if alternative medications that do not interfere with the test are appropriate for the few day period that some specific medications may need to be held.
Before the test:
- Do not smoke at least 20 minutes before the test.
- Do not take over the counter medications 7 days prior to the test without consulting our physician.
- Do not use any lotions, deodorants, creams or any topical medications for 48 hours prior to the testing.
- Avoid excessive amounts of caffeine for 4 hours prior to the test.
- Eat lightly and do not drink hot or iced beverages for 2 hours prior to the test.
Treatment of Complex Regional Pain Syndrome
Treatment of CRPS generally includes mobilization of the involved area and physical therapy. This may be a difficult balance, as activity may be painful, but immobilization or splinting of the involved area generally predisposes to further progression of the condition. Medications are employed that are targeted at different aspects of the problem. Generally, treatment involves use of anti-neuritic medications such as gabapentin or pregabalin, as well as centrally acting agents such as duloxetine (or use all trade names), and frequently topical agents are utilized which target receptors directly in the areas of involved skin. Analgesic medications may be required to treat pain.
An important aspect of the treatment of Complex Regional Pain Syndrome is the use of injections that temporarily interrupt the function of the sympathetic nervous system. Improvement following these “blocks” may vary from mild response to resolution of symptoms, and may last from short periods to long term improvement. Frequently, if a patient receives improvement from an initial block, repeat blocks may provide more marked and longer term relief. Frequently used injections include injections to anesthetize the sympathetic nervous system for either a right or left arm or leg (sympathetic block). Some patients respond better to more central injections (epidural steroid injections) together with blocks of involved peripheral nerves.
Blocks are used more frequently in the initial and early treatment of CRPS, and have a much more limited role in chronic management of the condition. Multiple Colorado Rehabilitation and Occupational Medicine physicians are skilled in performing these injections.
As the cause of Complex Regional Pain Syndrome is not understood, the severity of the condition varies greatly, and there are multiple different potential treatment approaches, treatment of this condition is individualized, and there is no single approach to treatment that is appropriate for all patients with this condition.